The
Oppau explosion occurred on September 21 1921 when a
tower siloA silo is a structure for storing bulk materials. Silos are used in agriculture to store grain or fermented feed known as silage. Silos are more commonly used for bulk storage of grain, coal, cement, carbon black, wood chips, food products and sawdust...
storing 4,500 tonnes of a mixture of
ammonium sulfateAmmonium sulfate , 2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions...
and
ammonium nitrateThe chemical compound ammonium nitrate, the nitrate of ammonia with the chemical formula NH4NO3, is a white crystalline solid at room temperature and standard pressure...
fertilizerFertilizers are chemical compounds applied to promote plant and fruit growth. Fertilizers are usually applied either through the soil or by foliar feeding...
exploded at a
BASFBASF SE is a German chemical company and the largest chemical company in the world. BASF originally stood for Badische Anilin- und Soda-Fabrik . Today, the four letters are a registered trademark and the company is listed on the Frankfurt Stock Exchange, London Stock Exchange, and Zurich Stock...
plant in
OppauOppau may refer to* Ludwigshafen-Oppau, a suburb of Ludwigshafen, Germany** the Oppau explosion which occurred there in 1921* until 1945, Opawa, Lower Silesian Voivodeship, Poland...
, now part of Ludwigshafen,
GermanyGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
, killing 500–600 people and injuring about 2,000 more.
The plant began producing ammonium sulfate in 1911, but during
World War IWorld War I , also known as the First World War, the Great War, and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente and the Triple Alliance...
when Germany was unable to obtain the necessary
sulfurSulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant, multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element and as sulfide and sulfate minerals...
, it began to produce ammonium nitrate as well.
The
Oppau explosion occurred on September 21 1921 when a
tower siloA silo is a structure for storing bulk materials. Silos are used in agriculture to store grain or fermented feed known as silage. Silos are more commonly used for bulk storage of grain, coal, cement, carbon black, wood chips, food products and sawdust...
storing 4,500 tonnes of a mixture of
ammonium sulfateAmmonium sulfate , 2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions...
and
ammonium nitrateThe chemical compound ammonium nitrate, the nitrate of ammonia with the chemical formula NH4NO3, is a white crystalline solid at room temperature and standard pressure...
fertilizerFertilizers are chemical compounds applied to promote plant and fruit growth. Fertilizers are usually applied either through the soil or by foliar feeding...
exploded at a
BASFBASF SE is a German chemical company and the largest chemical company in the world. BASF originally stood for Badische Anilin- und Soda-Fabrik . Today, the four letters are a registered trademark and the company is listed on the Frankfurt Stock Exchange, London Stock Exchange, and Zurich Stock...
plant in
OppauOppau may refer to* Ludwigshafen-Oppau, a suburb of Ludwigshafen, Germany** the Oppau explosion which occurred there in 1921* until 1945, Opawa, Lower Silesian Voivodeship, Poland...
, now part of Ludwigshafen,
GermanyGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
, killing 500–600 people and injuring about 2,000 more.
The plant began producing ammonium sulfate in 1911, but during
World War IWorld War I , also known as the First World War, the Great War, and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente and the Triple Alliance...
when Germany was unable to obtain the necessary
sulfurSulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant, multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element and as sulfide and sulfate minerals...
, it began to produce ammonium nitrate as well. Ammonia could be produced without overseas resources, using the
Haber processThe Haber process, also called the Haber–Bosch process, is the nitrogen fixation reaction of nitrogen gas and hydrogen gas, over an enriched iron catalyst, to produce ammonia. The Haber process is important because ammonia is difficult to produce on an industrial scale, and the fertilizer...
.
Compared to ammonium sulfate, ammonium nitrate is strongly hygroscopic, so the mixture of ammonium sulfate and nitrate clogged together under the pressure of its own weight, turning it into a plaster-like substance in the 20 m high silo. The workers needed to use
pickaxeA pickaxe is a hand tool with a hard head attached perpendicular to the handle.Some people make the distinction that a pickaxe has a head with a pointed end and a flat end, and a pick has both ends pointed, or only one end; but most people use the words to mean the same thing.The head is usually...
s to get it out, a problematic situation because they could not enter the silo and risk being buried in collapsing fertilizer.
To ease their work, small charges of
dynamiteDynamite is an explosive material based on the explosive potential of nitroglycerin, initially using diatomaceous earth or another absorbent substance such as sawdust as an absorbent...
were used to loosen the mixture. The procedure was tried experimentally and was considered safe; it was not known at the time that ammonium nitrate was explosive. Nothing extraordinary happened during an estimated 20,000 firings, until the fateful explosion on September 21. As all involved died in the explosion, the causes are not clear. A theory is that the mixture changed and a higher concentration of ammonium nitrate was present.
Scale of the explosion
The explosion was estimated to be equivalent to about 1–2 kilotonnes of TNT and was heard as a loud bang in
MunichMunich is the capital city of Bavaria, Germany. It is located on the River Isar north of the Bavarian Alps. Munich is the third largest city in Germany, after Berlin and Hamburg...
, more than 300 km away. The pressure wave ripped roofs off up to 25 km away and destroyed windows even farther away. In
HeidelbergHeidelberg is a city in Baden-Württemberg, Germany. As of 2008, over 145,000 people live within the city's area. Heidelberg is a unitary authority...
(30 km from Oppau), traffic was stopped by the mass of broken glass on the streets.
About 80 percent of all buildings in Oppau were destroyed, leaving 6,500 homeless. At
ground zeroThe term ground zero may be used to describe the point on the earth's surface where an explosion occurs...
a 90 m by 125 m
craterA subsidence crater is a hole or depression left on the surface of an area which has had an underground explosion. Many such craters are present at the Nevada Test Site, which is no longer in use for nuclear testing....
, 19 m deep, was created. Damages were estimated by New York Times in 1922 at then 321 million Marks (since Germany suffered heavy
hyperinflationIn economics, hyperinflation is inflation that is very high or "out of control", a condition in which prices increase rapidly as a currency loses its value....
in 1919–1924, given amounts and exchange-rates are not very descriptive).
According to some descriptions, only 450 tonnes exploded, out of 4,500 tonnes of fertilizer stored in the warehouse.
See also
- Texas City Disaster
The Texas City Disaster of April 16, 1947, started with the mid-morning fire and detonation of approximately 2,300 tons of ammonium nitrate on board the French-registered vessel SS Grandcamp in the port at Texas City, Texas, killing at least 581 people...
- a larger ammonium nitrate explosion
- List of the largest artificial non-nuclear explosions
External links